The present invention is related generally to downhauling sails in sailing craft. It is related in particular to tensioning sails of sailboards or windsurfing craft.
A conventional sailing craft such as a sailing dinghy or a yacht is generally equipped with sheets, halyards, winches and the like for adjusting the form and tension of one or more sails to suit wind and weather conditions and point of sail. Tension adjustments may be made while the craft is afloat and in motion.
A sailboard or windsurfing craft generally has only one sail. This sail must be tensioned before the craft is put afloat and may not be adjusted while the craft is afloat and in motion. Further, as windsurfing crafts are designed to travel at speeds up to forty-five knots, the one sail is generally placed under a high degree of tension to prevent the sail from being deformed by its motion through the air.
A windsurfing craft generally has only three major components, a board, a mast and a sail. Sailboards are designed to be stored with these three components disassembled and transported in this disassembled state to a point of use.
A windsurfing craft is assembled by attaching the sail to the mast and then attaching the sail and mast to the board. The sail generally has a sleeve at the leading edge or luff. The sail is attached to the mast by sliding the sleeve over the mast from the top of the mast. A cap at the top of the sleeve eventually limits travel of the sleeve down the mast. A rope or sheet (also referred to as a downhaul) is attached at one end to the base of the sail near to the mast. A free end of the sheet is passed through a cleat attached to the base of the mast. The cleat allows tension to be applied to the sail by pulling on or downhauling the portion of the sheet extending through the cleat. The cleat maintains the tension by preventing the sheet from returning through the cleat. Once the sail is tensioned, the mast is attached by its base to a mast cup flexibly mounted on the board, and the assembly is complete.
To optimally tension the sail requires the application of substantial force, generally such that a person of average strength would be required to pull on the sheet with both arms and attempt to brace against the mast with one or both feet. This may lead to injuries and abrasions due to slippage of the feet on the mast. In particular, it may lead to lower back injuries due to the awkward position which must be adopted to brace against the mast and downhaul the sail.
Clearly there is a need for a sail tensioning device for windsurfing craft which allows a person to tension a sail from a comfortable and safe attitude with the minimum of effort.